Capping apparatus for ink-jet printhead

ABSTRACT

A capping apparatus for an ink-jet printhead protects a printhead of an ink-jet cartridge moved to a service station by a carriage during a standby mode. The apparatus includes a cap which seals the lower surface of the ink-jet cartridge surrounding the printhead, is spaced from the printhead by a predetermined gap and forms a sealed space; a cap holder which is connected to the lower portion of the cap and supports the cap; and a support portion which is connected to the lower portion of the cap holder and attaches to and detaches the cap and the cap holder from the lower surface of the ink-jet cartridge. A boss which penetrates the cap holder is formed in the cap, and an insertion element inserted into the boss to form a vent path to connect the sealed space to the outside.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of Korean Application No.2002-40668, filed Jul. 12, 2002, in the Korean Intellectual PropertyOffice, the disclosure of which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a capping apparatus for an ink-jetprinthead, and more particularly, to a capping apparatus which includesa vent path to connect to the outside a space in which a printhead of anink-jet cartridge is sealed.

2. Description of the Related Art

A carrier which receives an ink-jet cartridge and reciprocates along aguide rod is provided in an ink-jet printer. The carrier reciprocatesalong the guide rod during printing. However, during a standby mode orwhen the carrier is not used for a long time, the carrier is moved to aservice station provided at one side of the guide rod. In this case, theprinthead of the ink-jet cartridge is sealed with a cap so as to preventdrying of ink in the nozzles, and contamination from dust.

However, when the printhead is sealed with the cap, when ambienttemperature increases, the pressure in a sealed space formed between theprinthead and the cap increases. Thus, the meniscus of the nozzles ofthe printhead is destroyed by the increased pressure in the sealedspace, and printing quality deteriorates.

To solve this problem, as shown in FIG. 1, U.S. Pat. No. 5,867,184discloses a universal cap 10 which seals a printhead (not shown) and hasa vent path to connect a sealed space to the outside.

Referring to FIG. 1, a sealing lip 12 is positioned on a cap body 11.The sealing lip 12 forms a sealed space between the sealing lip 12 andthe printhead while surrounding nozzles (not shown) of the printhead. Inaddition, although not shown, a groove is formed on the cap body 11 towhich the sealing lip 12 is attached. The groove serves as a vent pathand one end of the groove passes through the cap body 11 and connectsthe sealed space to the outside.

However, the universal cap 10 has a structure in which the sealing lip12 is attached to the cap body 11. This structure is complicated, andthus it is difficult to manufacture the universal cap 10. Further, thearea in which where the sealing lip 12 is attached to the cap body 11 issmall. Thus, when the universal cap 10 is used for a long time, thesealing lip 12 may be detached from the cap body 11, and sealing of theprinthead cannot be smoothly performed.

SUMMARY OF THE INVENTION

Accordingly, it is an object of the present invention to provide acapping apparatus for an ink-jet printhead which seals the ink-jetprinthead, forms a simple vent path to connect a sealed space to theoutside and does not cause sealing problems when the capping apparatusis used for a long time.

Additional objects and advantages of the invention will be set forth inpart in the description which follows and, in part, will be obvious fromthe description, or may be learned by practice of the invention.

The foregoing and/or other objects are achieved by providing a cappingapparatus which protects a printhead of an ink-jet cartridge moved to aservice station by a carriage during a standby mode, the apparatusincluding a cap which seals a lower surface of the ink-jet cartridgesurrounding the printhead, is spaced from the printhead by apredetermined gap, and forms a sealed space; a cap holder which isconnected to a lower portion of the cap and supports the cap; a supportportion which is connected to a lower portion of the cap holder andattaches to and detaches the cap and the cap holder from a lower surfaceof the ink-jet cartridge, wherein a boss which penetrates the cap holderis formed in the cap; and an insertion element inserted into the boss toform a vent path to connect the sealed space to an outside.

The insertion element may include a cylindrical column inserted into theboss, and a thread formed around the cylindrical column. The diameter ofthe cylindrical column may be smaller than the inner diameter of theboss, and the outer diameter of the insertion element including thethread may be larger than the inner diameter of the boss.

In addition, a head part is formed on the cylindrical column so as tocover the top portion of the boss, and a hole is formed in the headpart. The hole is connected to a groove formed between the thread and aninner surface of the boss and connects the sealed space to the outside.The insertion element may be formed spirally.

The insertion element according to a modified example may be acylindrical column in the outer wall of which a vertical groove isformed, or a cylindrical column in which a vertical through hole isformed. The cap may be formed of an elastomeric material, and theinsertion element and the cap holder may be formed of a plasticmaterial.

The boss may project a predetermined height toward the printhead. Ahollow cylinder projecting toward the cap holder may be formed in thesupport portion, and an extrusion column may be formed under the capholder. The extrusion column extends to the support portion and isinserted into the cylinder. An elastic spring may be formed around thecylinder to provide an elastic force so that the cap closely contactsthe lower surface of the ink-jet cartridge.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other objects and advantages of the invention will becomeapparent and more readily appreciated from the following description ofthe preferred embodiments, taken in conjunction with the accompanyingdrawings of which:

FIG. 1 is a perspective view of a conventional universal cap;

FIG. 2 is a cross-sectional view illustrating a capping apparatus for anink-jet printhead according to an embodiment of the present inventionwhich seals a printhead of an ink-jet cartridge;

FIG. 3 is a perspective view illustrating portion of the cappingapparatus of FIG. 2;

FIG. 4 is a cross-sectional view taken along line IV—IV of FIG. 3,showing a first type of insertion element; and

FIGS. 5 and 6 illustrate second and third types of insertion elementsaccording to the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Reference will now be made in detail to the present preferredembodiments of the present invention, examples of which are illustratedin the accompanying drawings, wherein like reference numerals refer tolike elements throughout. In the drawings, the thicknesses of layers orregions are exaggerated for clarity.

FIG. 2 is a cross-sectional view illustrating a capping apparatus 100for an ink-jet printhead according to an embodiment of the presentinvention which seals a printhead 103 of an ink-jet cartridge 102.Referring to FIG. 2, the printhead 103 is positioned on the lowersurface of the ink-jet cartridge 102. A plurality of nozzles 104 throughwhich ink is ejected are formed in the printhead 103. A cap 110 isspaced from the printhead 103 by a predetermined gap and surrounds theprinthead 103. A cap holder 120, which supports the cap 110, is providedunder the cap 110. A support portion 130, which supports the cap holder120, is provided under the cap holder 120. An extrusion column 122 isformed under the cap holder 120. The extrusion column 122 is insertedinto a hole of a cylinder 132 that is formed in the support portion 130,and is configured to move upward and downward through the hole of thecylinder 132. The downward movement of the extrusion column 122 isconfined by a support jaw 134 formed at edges of the support portion 130or the top portion of the cylinder 132. An elastic spring 136 isprovided around the cylinder 132, provides an elastic force so that thecap holder 120 and the cap 110 move upward from the cylinder 132, andthus, the cap 110 seals the lower surface of the ink-jet cartridge 102.

The support portion 130 is connected to a mechanism (not shown) to movethe support portion 130 so that the cap 110 contacts the lower surfaceof the ink-jet cartridge 102 when the inkjet cartridge 102 moves to aservice station with a carriage (not shown) during a standby mode. Inthe present embodiment, the support portion 130 is connected to arotation portion 140 and is attached to and is detached from the lowersurface of the ink-jet cartridge 102 by the rotation portion 140. Oneside of the rotation portion 140 is fixed by a connection pin 142, theother side of the rotation portion 140 is connected to the supportportion 130 and rotates centering on the connection pin 142. Theconnection pin 142 is fixed in a housing 144 that is provided formaintenance of a printer body or printhead. While a mechanism to rotatethe support portion 130 is shown in the present embodiment, the supportportion 130 may alternately be connected to a mechanism to move thesupport portion 130 upward and downward.

FIG. 3 is a perspective view illustrating portions of the cappingapparatus 100 of FIG. 2, and FIG. 4 is a cross-sectional view takenalong line IV—IV of FIG. 3.

Referring to FIGS. 3 and 4, the cap 110 includes a plate 111 as a body,a sealing lip 112 which extends toward the ink-jet cartridge 102 fromedges of the plate 111 and forms a sealed space surrounding theprinthead 103, a boss 113 which is shaped to penetrate the plate 111,and an insertion element 150 which is inserted into the boss 113 andforms a vent path between an inner surface of the boss 113 and theinsertion element 150.

The boss 113 is projected a predetermined height which is lower than thesealing lip 112 relative to the upper surface of the plate 111 andprevents waste ink and dust stacked on the plate 111 from flowing intothe boss 113. In addition, the boss 113 projects to a predeterminedlength from the lower surface of the plate 111 downward and provides thelength of the vent path, which is to be described later. A hole having apredetermined diameter is formed in the boss 113.

The insertion element 150 according to the present embodiment includes acylindrical column 151, a thread 153 formed spirally around thecylindrical column 151, and a head part 152 formed on the cylindricalcolumn 151.

The cap 110 may be formed of an elastomeric material such as rubber, andthe insertion element 150 may be formed of a plastic material. The outerdiameter of the cylindrical column 151 formed by the thread 153 islarger than the inner diameter of the boss 113, and the inner diameterof the cylindrical column 151 is smaller than the inner diameter of theboss 113. Thus, the insertion element 150 is inserted into the hole ofthe boss 113 and then forms the vent path spirally along the thread 153.

In the present embodiment, the inner diameter of the boss 113 isapproximately 2.4 mm and the outer and inner diameters of the insertionelement 150 are approximately 2.5 mm and 2.1 mm, respectively, and thusthe height of the thread 153 is approximately 0.2 mm.

A hole 152 a is formed in the head part 152 contacting the vent path andconnects the sealed space formed by the cap 110 to the outside throughthe vent path. The cap holder 120 may be formed of a plastic material sothat the elastic force from the spring 136 is conveyed to the cap 110.

The function of the capping apparatus 100 for an ink-jet printheadhaving the above structure will be described in detail with reference tothe drawings.

Referring to the drawings, if the ink-jet cartridge 102 moves to theservice station during a standby mode, the capping apparatus 100connected to the connection pin 142 rotates, and the sealing lip 112contacts the lower surface of the ink-jet cartridge 102. In this case,if the cap 110 and the cap holder 120 are moved downward by the ink-jetcartridge 102 and compress the spring 136, the extrusion column 122moves slightly downward. In this case, the compressed depth of theinserted extrusion column 122 is confined by the support jaw 134 formedat the edges of the support portion 130. Thus, the compressed spring 136provides an elastic force so that the cap 110 moves toward the lowersurface of the ink-jet cartridge 102 from the support portion 130. Thus,the cap 110 forms the sealed space surrounding the printhead 103 on thelower surface of the ink-jet cartridge 102.

When the printer is not used for a long time, if an ambient temperatureincreases, the inner surface of the sealed space expands, and highpressure is generated. In this case, air in the sealed space flows intothe hole 152 a formed in the head part 152 of the insertion element 150,and is exhausted through the vent path. Thus, a predetermined range ofpressure is maintained in the sealed space. As a result, the printhead103 is protected from external temperature variations, and ink isnormally ejected through nozzles 104 of the printhead 103 when theprinter restarts.

FIG. 5 illustrates another example of an insertion element.

Referring to FIG. 5, an insertion element 250 inserted into the boss 113of the cap 110 includes a cylindrical column 251 in the outer wall ofwhich a vertical groove 253 is formed, and a head part 252 formed on thecylindrical column 251. A hole 252 a is formed in the head part 252contacting the vertical groove 253 and connects the vent path formedbetween the inner surface of the boss 113 and the insertion element 250to the sealed space. A diameter of the cylindrical column 251 is largerthan an inner diameter of the boss 113, and a length obtained bysubtracting a depth of the groove 253 from the diameter of thecylindrical column 251 is smaller than the inner diameter of the boss113. As a result, the vertical groove 253 forms a well-sealed vent pathwhen the insertion element 250 is inserted into the hole of the boss113.

FIG. 6 illustrates another example of an insertion element.

Referring to FIG. 6, an insertion element 350 inserted into the boss 113of the cap 110 includes a cylindrical column 351 in which a verticalthrough hole 353 is formed, and a head part 352 formed on thecylindrical column 351. A hole 352 a is formed in the head part 352contacting the through hole 353 and connects the vent path formedbetween the inner surface of the boss 113 and the insertion element 350to the sealed space. The diameter of the insertion element 350 may belarger than the inner diameter of the boss 113. As a result, the throughhole 353 forms the vent path when the insertion element 350 is insertedinto the hole of the boss 113.

The functions of the insertion elements 250, 350 are similar to thefunction of the insertion element 150.

As described above, in the capping apparatus for an ink-jet printheadaccording to the present invention, the printhead of the ink-jetcartridge can be sealed, and simultaneously the vent path to connect thesealed space to the outside can be simply formed. In addition, theinsertion element having a large outer diameter is inserted into theboss, thereby achieving an efficient seal.

Although a few preferred embodiments of the present invention have beenshown and described, it will be appreciated by those skilled in the artthat changes may be made in these embodiments without departing from theprinciples and spirit of the invention, the scope of which is defined inthe claims and their equivalents.

1. A capping apparatus which protects a printhead of an ink-jetcartridge moved to a service station by a carriage during a standbymode, the apparatus comprising: a cap which seals a lower surface of theink-jet cartridge surrounding the printhead, is spaced from theprinthead by a predetermined gap, and forms a sealed space; a cap holderwhich is connected to a lower portion of the cap and supports the cap; asupport portion which is connected to a lower portion of the cap holderand attaches to and detaches from the cap and the cap holder from alower surface of the ink-jet cartridge, wherein a boss which penetratesthe cap holder is formed in the cap; and an insertion element fixedlyinstalled inside the boss, to form a vent path to connect the sealedspace to an outside.
 2. The apparatus of claim 1, wherein the insertionelement comprises: a cylindrical column inserted into the boss; and athread formed around the cylindrical column, and the thread forms thevent path.
 3. The apparatus of claim 2, wherein a diameter of thecylindrical column is smaller than an inner diameter of the boss, and anouter diameter of the insertion element including the thread is largerthan the inner diameter of the boss.
 4. The apparatus of claim 2,wherein a groove is formed between the thread and an inner surface ofthe boss, and the insertion element comprises: a head part formed on thecylindrical column so as to cover a top portion of the boss, and a holeis formed in the head part to connect to the groove and to connect thesealed space to the outside.
 5. The apparatus of claim 4, wherein theinsertion element is formed spirally.
 6. The apparatus of claim 1,wherein the insertion element is a cylindrical column having an outerwall and a vertical groove formed on the outer wall, and the verticalgroove forms the vent path.
 7. The apparatus of claim 6, wherein adiameter of the cylindrical column is larger than an inner diameter ofthe boss, and a length obtained by subtracting a depth of the groovefrom the diameter of the cylindrical column, is smaller than the innerdiameter of the boss.
 8. The apparatus of claim 6, further comprising: ahead part formed on the insertion element to cover a top portion of theboss; and a hole, formed in the head part, which is connected to thegroove and connects the sealed space to the outside.
 9. The apparatus ofclaim 1, wherein the insertion element is a cylindrical column in whicha vertical through hole is formed, and the vertical through hole formsthe vent path.
 10. The apparatus of claim 9, wherein a diameter of thecylindrical column is larger than an inner diameter of the boss beforethe installation of the insertion element inside the boss.
 11. Theapparatus of claim 9, further comprising: a head part formed on thecylindrical column to cover a top portion of the boss; and a hole,formed in the head part, which is connected to the through hole andconnects the sealed space to the outside.
 12. The apparatus of claim 1,wherein the cap is formed of an elastomeric material, and the insertionelement and the cap holder are formed of a plastic material.
 13. Theapparatus of claim 1, wherein the boss projects to a predeterminedheight toward the printhead.
 14. The apparatus of claim 1, furthercomprising: a hollow cylinder projecting toward the cap holder, formedin the support portion; and an extrusion column which extends to thesupport portion and inserted into the cylinder, the extrusion columnbeing formed under the cap holder.
 15. The apparatus of claim 14,further comprising an elastic spring formed around the cylinder toprovide an elastic force so that the cap closely contacts a lowersurface of the ink-jet cartridge.
 16. A capping apparatus which protectsa printhead of an ink-jet cartridge moved to a service station by acarnage during a standby mode, the apparatus comprising: a cap whichseals a lower surface of the ink-jet cartridge surrounding theprinthead, is spaced from the printhead by a predetermined gap, andforms a sealed space; a cap holder which is connected to a lower portionof the cap and supports the cap; a support portion which is connected toa lower portion of the cap holder and attaches to and detaches from thecap and the cap holder from a lower surface of the ink-jet cartridge,wherein a boss which penetrates the cap holder is formed in the cap; andan insertion element inserted into the boss to form a vent path along alength of the vent path to connect the sealed space to an outside. 17.An apparatus to protect an ink-jet cartridge, the apparatus comprising:a cap to contact the ink-jet cartridge to form a sealed spacetherebetween; a press unit to press the cap against the ink-jetcartridge to maintain the sealed space; and a vent element inserted intothe cap to form a vent path along a length of the vent element toconnect the sealed space to an outside; wherein the vent element extendsa predetermined height above a lower inner surface of the cap.
 18. Aprinting apparatus comprising: an ink-jet cartridge; a housing; and acapping apparatus to protect the ink-jet cartridge, the apparatuscomprising: a cap to contact the ink-jet cartridge to form a sealedspace therebetween, a support portion in contact with the housing tosupport the cap, a press unit between the cap and the support portion topress the cap against the ink-jet cartridge to maintain the sealedspace, and a vent element inserted into the cap to form a vent pathalong a length of the vent element to connect the sealed space to anoutside; wherein the vent element extends a predetermined height above alower inner surface of the cap.